How Homeowners Pay for an ADU
Home equity, cash-out refinance, construction and renovation loans: how homeowners commonly pay for an ADU, and what lenders look at before approving.
Two things have to exist before a lender conversation is worth having: a written scope specific enough that the number attached to it means something, and an honest figure for what you can cover out of pocket. Many homeowners work the other way. They pick a loan product, then squeeze the project into it.
We build ADUs. We are not a lender, a mortgage broker, or a financial advisor, and none of this is advice about your situation. Below is a plain description of the categories homeowners commonly use. The decision itself belongs with a licensed lender or a financial professional.
The question that sorts the options
Financing an ADU splits along one line. Either you borrow against equity you already hold, or against what the property should be worth once the unit is finished. That decides which products are open to you, whether money arrives at once or in stages, and how much paperwork your contractor produces.
Categories homeowners commonly use
Home equity loan or line of credit
A home equity loan pays a lump sum. A line of credit lets you draw as you go. Both sit behind your existing first mortgage and are sized off the property's current value, not its finished value. The constraint appears when the equity you hold today does not reach the project you want.
Cash-out refinance
Your existing mortgage is replaced with a larger one and you take the difference in cash. Whether that trade makes sense depends entirely on the terms you already have against the terms available now. A mortgage professional can run that comparison for you. A contractor cannot, and should not try.
Construction loan
Designed for ground-up work. Funds release in stages as phases are completed and inspected, rather than landing in your account at closing. Underwriting often rests on an appraisal of the property as completed, and the lender will want plans, a line-item budget, a schedule, and documentation on the builder.
Renovation loan programs
Certain purchase and refinance programs allow improvement costs to be folded into the loan and underwritten against the improved value. Government-backed and conventional versions both exist. Expect more administration and stricter rules about disbursement and about who performs the work. Not every lender originates them, so ask early.
Savings and other personal funds
Simplest to administer, with no underwriting and no draw schedule to coordinate. The risk is emptying the account and having nothing left the week the sewer lateral turns out to need replacing.
What lenders generally look at
- Credit history and score
- Income against your existing debt obligations
- Equity in the property, or its projected value once the unit is complete
- An appraisal, ordered by them rather than by you
- The signed contract, the plans, and the construction budget
- Your contractor: license status, insurance, and sometimes references
That last item catches people off guard. On construction and renovation products the lender is underwriting the builder alongside the borrower. Whether projected rent from the finished unit helps you qualify varies by program and by lender, so ask directly instead of assuming either way.
Where this commonly goes sideways
Borrowing the contract amount and nothing beyond it. Real projects generate change orders, and a loan sized exactly to the original contract leaves you funding surprises out of your checking account. Ask your lender how borrowers in your position size a contingency into the loan amount.
A draw schedule that fights the payment schedule. Lenders release money after an inspector confirms a phase is finished. Contracts frequently call for payment at the start of a phase. Reconcile those two documents before you sign either one, because renegotiating mid-build is considerably harder.
Signing a construction contract on a pre-approval. Pre-approval is not funding. If the appraisal lands differently than expected, you can end up contractually committed with nothing behind it.
Oversized deposits. California limits what a contractor may collect as a down payment on most home improvement contracts, and there are exceptions to that limit. The CSLB publishes the current rule at cslb.ca.gov. If the amount someone is asking for concerns you, confirm it there or with an attorney rather than taking the contractor's word for it. If someone asks for a large sum before any work begins, check it against that rule rather than taking their word for it.
Financing arranged by the contractor. Some builders offer or broker it. That is not automatically a problem, though it deserves comparison against an offer you sourced yourself. Pressure to use the in-house option tells you whose interests are being served.
What your contractor should hand you
Most documents a lender wants come from the builder: a written scope, permit-ready plans, a line-item budget, a schedule, current license and insurance certificates, and signed change orders as the job moves. We prepare those. Ask whoever you are considering whether they have worked inside an inspection-based draw before. The ones who have will not need it explained. Our license is 1063782, verifiable at cslb.ca.gov.